[Intel-wired-lan] [PATCH net v2] iavf: Fix asynchronous tasks during driver remove

[Eryk Rybak <eryk.roch.rybak@intel.com>]

Although rare, is possible for unexpected driver watchdog or Admin
Queue tasks to run during the execution of iavf_remove function.
Then, is not possible to obtain the standard __IAVF_IN_CRITICAL_TASK
lock and difficult to ensure that the driver state stays consistent
during the full removal process.

Fully stops all asynchronous tasks in the beginning of iavf_remove,
and uses a single-threaded flow to shut down the driver.

Fixes: fdd4044ffdc8("iavf: Remove timer for work triggering, use delaying work instead")
Signed-off-by: Nick Nunley <nicholas.d.nunley@intel.com>
Signed-off-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Signed-off-by: Eryk Rybak <eryk.roch.rybak@intel.com>
---
 drivers/net/ethernet/intel/iavf/iavf_main.c | 31 +++++++++++++++++----
 1 file changed, 25 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/intel/iavf/iavf_main.c b/drivers/net/ethernet/intel/iavf/iavf_main.c
index dc5b3c06d1e0..e752ecb7ad89 100644
--- a/drivers/net/ethernet/intel/iavf/iavf_main.c
+++ b/drivers/net/ethernet/intel/iavf/iavf_main.c
@@ -1887,6 +1887,12 @@ static void iavf_watchdog_task(struct work_struct *work)
 	struct iavf_hw *hw = &adapter->hw;
 	u32 reg_val;
 
+	/* If the driver is in the process of being removed then don't run or
+	 * reschedule the watchdog task.
+	 */
+	if (test_bit(__IAVF_IN_REMOVE_TASK, &adapter->crit_section))
+		return;
+
 	if (test_and_set_bit(__IAVF_IN_CRITICAL_TASK, &adapter->crit_section))
 		goto restart_watchdog;
 
@@ -2267,6 +2273,12 @@ static void iavf_adminq_task(struct work_struct *work)
 	u32 val, oldval;
 	u16 pending;
 
+	/* If the driver is in the process of being removed then return
+	 * immediately and don't re-enable the Admin Queue interrupt.
+	 */
+	if (test_bit(__IAVF_IN_REMOVE_TASK, &adapter->crit_section))
+		return;
+
 	if (adapter->flags & IAVF_FLAG_PF_COMMS_FAILED)
 		goto out;
 
@@ -3245,6 +3257,13 @@ static int iavf_close(struct net_device *netdev)
 
 	clear_bit(__IAVF_IN_CRITICAL_TASK, &adapter->crit_section);
 
+	/* If the interface is closing as part of driver removal it doesn't
+	 * wait. The VF resources will be reinitialized when the hardware is
+	 * reset.
+	 */
+	if (test_bit(__IAVF_IN_REMOVE_TASK, &adapter->crit_section))
+		return 0;
+
 	/* We explicitly don't free resources here because the hardware is
 	 * still active and can DMA into memory. Resources are cleared in
 	 * iavf_virtchnl_completion() after we get confirmation from the PF
@@ -3850,11 +3869,16 @@ static void iavf_remove(struct pci_dev *pdev)
 	struct iavf_cloud_filter *cf, *cftmp;
 	struct iavf_hw *hw = &adapter->hw;
 	int err;
-	/* Indicate we are in remove and not to run reset_task */
+	/* Indicate that program driver is remove task and not
+	 * to run/schedule any driver tasks
+	 */
 	set_bit(__IAVF_IN_REMOVE_TASK, &adapter->crit_section);
 	cancel_delayed_work_sync(&adapter->init_task);
 	cancel_work_sync(&adapter->reset_task);
 	cancel_delayed_work_sync(&adapter->client_task);
+	cancel_work_sync(&adapter->adminq_task);
+	cancel_delayed_work_sync(&adapter->watchdog_task);
+	iavf_misc_irq_disable(adapter);
 	if (adapter->netdev_registered) {
 		unregister_netdev(netdev);
 		adapter->netdev_registered = false;
@@ -3879,15 +3903,10 @@ static void iavf_remove(struct pci_dev *pdev)
 	}
 	iavf_free_all_tx_resources(adapter);
 	iavf_free_all_rx_resources(adapter);
-	iavf_misc_irq_disable(adapter);
 	iavf_free_misc_irq(adapter);
 	iavf_reset_interrupt_capability(adapter);
 	iavf_free_q_vectors(adapter);
 
-	cancel_delayed_work_sync(&adapter->watchdog_task);
-
-	cancel_work_sync(&adapter->adminq_task);
-
 	iavf_free_rss(adapter);
 
 	if (hw->aq.asq.count)

base-commit: c1acda9807e2bbe1d2026b44f37d959d6d8266c8
-- 
2.20.1